The isolation of individual colonies of micro-organisms (and in particular bacteria) is an important procedure in many microbiological laboratories. This isolation of bacteria is normally done either manually by skilled laboratory technologists or automatically by robotic streaking equipment. In either case, a microbiological sample is first dispensed upon the surface of a solid culture medium followed by the spreading of the microbiological sample across the surface of the medium (called “streaking”). Typically, multiple streaks are made of increasing dilution of the inoculum across the solid culture medium.
The streaks of increasing dilution tend to provide, generally towards the tail of the streaks, a number of single cells that allow for the growth of isolated microbiological colonies after incubation. These isolated colonies may then be analysed for various physical features e.g. colony morphology, and may undergo staining and other procedures which may be necessary for determining, for example, the genus, the species and/or the strain of the previously unidentified organism in the microbiological sample.
Traditionally, this analysis has been carried out visually in a microbiological laboratory by skilled technologists, resulting in the technologist making a microbiological assessment. This assessment may be based on the detection of the presence or absence of bacterial colonies, the detection of colour(s) of each colony type, the mapping of colour distribution to determine the presence of variations in colour which could be attributed to fermentation or haemolysis, the differentiation between confluent and isolated colony growth, the measurement of colony texture or viscosity, and the determination of two-dimensional and three-dimensional shape, and/or enumeration of the different types of colonies.
Where growth of potentially pathogenic bacteria is identified, the solid culture medium is progressed to the next step of the laboratory workflow and becomes the subject of further confirmatory identification and antibiotic susceptibility testing, in line with current regulatory requirements.
It is an aim of the present invention to provide a method and software for analysing images in order to provide a microbiological assessment, where this assessment is generated without any (or with only minor) human operator intervention.
Before turning to a summary of the present invention, it must be appreciated that the above description of the prior art has been provided merely as background to explain the context of the invention. It is not to be taken as an admission that any of the material referred to was published or known, or was a part of the common general knowledge in Australia or elsewhere.